Ammunition



Aug. 11, 1936. F FALLON 2,050,692

AMMUNITION Filed Dec. 5, 1933 INVENTOR Thomas E Fa //0/7 WW, EIMZ MW A ATTORNEYS Patented Aug. 11, 1936 STAT )5 ATENT OFFICE AMMUNITION Application December 5, 1933, Serial No. 700,973

6 Claims.

This invention relates to cartridges for small arms ammunition, more particularly to shot gun cartridges, and it comprises a method of and apparatus for corrugating the outer surface of the tube or case.

It has been proposed to corrugate the outer surface of paper tubes used for making shot gun cartridges or rifle cartridges. Such a product is disclosed in the British patent to Ambjorn No. 2295 of 1887. My invention relates particularly to means whereby a tube having a corrugated outer surface may be readily produced in the standard ammunition manufacturing plant.

Heretofore efforts to corrugate the exterior surface of a cartridge tube have not been entirely successful. In the manufacture of tubes for shot gun cartridges several tubes are cut from a tube blank. It has been proposed to corrugate the outer surface of the blank by placing the tube blank on a mandrel and feeding it through a corrugating die. However, the resistance which is encountered in the passage of the tube blank through the die makes it necessary to anchor the tube blank to the mandrel to prevent relative movement of the tube and mandrel and so far as I am aware no one has successfully found a methd of so anchoring the tube blank, which method may be employed in the ammunition manufacturing plant without interfering with the normal sequence of steps in the manufacture of cartridges.

I have found that this difficulty may be overcome by forming the surface of the mandrel so as to increase its gripping action on the tube. This may be done in several ways. The surface may be sand blasted, knurled, provided with a spiral corrugation or treated in other similar ways so that its gripping action on the tube blank is increased. While several of these methods may be employed, I have found that better results are obtained if a sand blasted mandrel is employed. Where the surface of the mandrel is knurled or provided with spiral corrugations, the pressure which is exerted when the mandrel and tube blank are being fed through the corrugating die, leaves the pattern of the surface of the mandrel on the interior of the tube. I have found that when a sand blasted mandrel is employed, the interior surface of the tube blank is smooth and I prefer this method to the other alternative methods outlined above.

In the accompanying drawing I have illustrated apparatus for carrying out the process of my invention and the product thereof.

Referring to the drawing,

Fig. 1 is a diagrammatic view showing the corrugating die with the mandrel and tube partially through it;

Fig. 2 is a detailed view of the corrugating die showing the corrugations;

Fig. 3 is a side elevation of the corrugated tube blank;

Fig. 4 is an end elevation thereof; and

Fig. 5 is a side view of a shot gun cartridge having the paper tube thereof corrugated.

Referring to the drawing, the reference numeral I designates a tube blank from which the tubes for a number of shot gun cartridges are to be cut. This tube is formed by rolling in the usual manner. Heretofore it has been the practice to pass the tube blanks through a burnishing and sizing die. The tube blank may be corrugated by using the apparatus heretofore employed for feeding it through the burnishing and sizing die.

In place of the die heretofore employed, I sub- 2 stitute a die 2, the interior of which is provided with corrugations 3. This die cooperates with a mandrel d on which the tube blank I is arranged,

as shown in Fig. 1 of the drawing, and the tube blank is fed through the die 2 to corrugate its outer surface by the movement of the mandrel through the die. A pair of rolls 5 having grooved surfaces are arranged in front of the die to engage the outer surface of the tube and press it against the mandrel. After passing through the die, the tube blank is provided with corrugations 6 on its outer surface, as shown in Figs. 3 and 4 of the drawing. This blank is then cut in sections of the proper length to form the tubes of shot gun cartridges or rifle cartridges and employed in the manufacture of such cartridges. Referring to Fig. 5 of the drawing wherein a completed shot gun cartridge is illustrated, the tube I having the corrugations 6 on its outer surface is arranged in a metal head I in the usual manner. The shot gun cartridge is, of course, provided with a primer, a load of propellant powder, a load of shot and suitable top and bottom wads, all of which are of conventional construction and are not illustrated.

As stated above, I have found that the passage of the tube I through the die 2 can be facilitated by treating or otherwise forming the surface of the mandrel 4 so as to more securely anchor the tube on the mandrel to prevent relative movement of the tube. This can be accomplished by sand blasting the surface of the mandrel and in the drawing I have illustrated a mandrel, the surface of which has been sand blasted. Likewise, the gripping of the tube by the mandrel can be increased by forming a spiral groove on the surface of the mandrel, knurling the surface or otherwise slightly roughening it to increase its gripping action.

My invention consists in the provision of suitable apparatus and a method for corrugating tube blanks to be used in the manufacture of shot gun cartridges and rifle Cartridges. The product so produced is'disclosed in British Patent NoLg2295 of war-heretofore referred to.

I claim:

1. The method of corrugating a paper tube blank of uniform diameter which comprises placing the blank on a mandrel having a cylindrical surface adapted to frictionally engage the inside of said blank to oppose relative longitudinal movement of said blank and mandrel, and feeding the mandrel with the blank thereon through a corrugating die. n

2. The method of corrugating a paper tube blank of uniform diameter which comprises placing the blankon a mandrel having a cylindrical surface adapted to frictionally engage the inside of said blank, pressing the walls of said blank against the cylindrical surface of the mandrel to increase the frictional engagement between said blank and mandrel, and feeding the mandrel with the blank pressed thereon through a corrugating die.

3. In an apparatus for corrugating paper tube blanks of uniform diameter, a corrugating die, and a mandrel longitudinally movable through said die and having a cylindrical surface adapted to frictionally engage the .inside of a tube blank arranged on said mandrel to prevent relative longitudinal movement of said tube blank and mandrel while the mandrel is being passed through said die.

4. In an apparatus for corrugating paper tube blanks, a corrugating die, and a mandrel longitudinally movable through said die and having a frictional surface adapted to engage the inside of a tube blank arranged on said mandrel to oppose relative longitudinal movement of said tube blank and mandrel, said frictional surface constituting the sole means for preventing longitudinal movement of said tube blank along the mandrel while the mandrel is being passed through said die.

5.7In an apparatus for corrugating paper tube 7 blanks, a corrugating die, and a mandrel longitudinally movable through said die and having a cylindrical surface adapted to engage the inside of a tube blank arranged on said mandrel, said cylindrical surface having a high coefficient of friction whereby the coefiicient of friction between said mandrel and tube blank is greater than that between the tube blank and said die.

6. In an apparatus for corrugating paper tube blanks, a corrugating die, a mandrel movable longitudinally through said die and having a cylindrical surface adapted to frictionally engage the inside of a tubeblank arranged on said mandrel to prevent longitudinal movement of said tube blank on the mandrel while the mandrel is being passed through said die, and means for pressing the walls of said tube blank against the mandrel prior to passing the tube blank through said die.

THOMAS F. FALLON. 

